Timing trigger switching method based on ephemeris and user position calculation

Abstract

The invention discloses a timing trigger switching method based on ephemeris and user position calculation, and belongs to the field of low-orbit satellite communication. The working principle is as follows: (1) a gateway station receives a position and speed measurement report periodically sent by a user, (2) the gateway station calculates and judges a target wave beam / satellite / gateway station and a switching mode according to the ephemeris; (3) a delta t1 value is calculated according to the conditions of the source gateway station, the target gateway station and the switching mode, (4) a toff-treport value and a delta t2 value are calculated based on the ephemeris and the user position; (5) pre-switching judgment is carried out according to the calculated value; (6) if a pre-switchingcondition is met, a timer is established; (7), pre-switching is initiated by the gateway station according to the timing of the timer; and (8), a switching command is issued to a user by the gateway station after the timing of the timer (toff-treport-delta t1-delta t2). By means of the method, the low-orbit satellite system switching preparation stage depends on gateway station calculation, the terminal does not need to conduct neighbor cell / wave beam pilot frequency measurement, the switching problem of a small wave beam overlapping area is effectively solved, and meanwhile the method is widely applied to various scenes of the low-orbit satellite system.

Description

technical field [0001] The invention belongs to the field of low-orbit satellite communication, and in particular relates to a timing trigger switching method based on ephemeris and user position calculation in a low-orbit satellite system. [0002] technical background [0003] With the development of global low-orbit satellite constellation construction, the problem of user switching under low-orbit satellite systems has become increasingly prominent. How to effectively complete user switching across beams, satellites, and gateways has become an important issue for low-orbit satellite systems to provide users with high-quality services. major problems to be solved. In the terrestrial mobile communication system, the problem of user cross-cell and cross-system handover has always been a key technology. From the development of 2G to 5G mobile communication systems, its technical solutions have been very mature. At present, handover technologies for terrestrial mobile communi...

AI Technical Summary

Problems solved by technology

However, for a low-orbit satellite system with a small beam overlapping area, if the ground mobile communication handover scheme is adopted, it cannot be guaranteed that the user will complete the entire handover process within the dwell time of the overlapping area, and even cannot guarantee that the terminal will measure the gap at different frequencies (the duration is about 6ms)

Under this design scheme, the handover judgment method of the system cannot adopt the handover judgment based on the signal strength measurement report of the adjacent cell as in the ground mobile communication.

On the other hand, the unilateral delay of downlink transmission in the low-orbit satellite system (satellite transparent forwarding) can reach tens of milliseconds, and the whole-process delay of the ground mobile communication system switching solution will be longer, which is not conducive to the user experience of frequent switching

[0006] To sum up, for the handover scheme of the low-orbit satellite system (satellite transparent forwarding) with a small beam overlapping area, there is no good solution at present, which can not only rely on the inter-frequency signal strength measurement report, but also can Reduce the switching process

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